Search Results (341)

Metastatic breast cancer (BC) spread underscores the need for novel prognostic biomarkers. This study investigated CCR4-NOT Transcription Complex Subunit 7 (CNOT7) and leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) in BC progression and natural killer (NK) cell resistance. In the current study, 90 female BC patients (46 non-metastatic, 44 metastatic) were analyzed. CNOT7 and LAIR-1 protein levels were measured in serum via ELISA and CNOT7 expression in tissue by immunohistochemistry (IHC). In silico tools explored related pathways. Computational analyses, including in silico bioinformatics and molecular docking, explored gene functions, interactions, and ligand binding to CNOT7 and LAIR-1. CNOT7 serum levels were significantly elevated in metastatic patients (mean 4.710) versus non-metastatic patients (mean 3.229, p < 0.0001). Conversely, LAIR-1 serum levels were significantly lower in metastatic (mean 56.779) versus non-metastatic patients (mean 67.544, p < 0.0001). High CNOT7 was found in 50% (45/90) of cases, correlating with higher tumor grade, hormone receptor negativity, and increased lymph node involvement. Elevated CNOT7 and lower LAIR-1 levels were associated with worse overall survival. Pathway analysis linked CNOT7 to the PI3K/AKT/mTOR pathway. Computational findings elucidated CNOT7′s cellular roles, gene/protein interaction networks for LAIR-1/CNOT7, and distinct ligand binding profiles. High CNOT7 levels are associated with advanced BC stages and poor clinical outcomes, which suggests its utility as a prognostic biomarker. The inverse relationship between CNOT7 and LAIR-1 provides mechanistic insights into BC progression and immune evasion, further supported by in silico investigations. Full article

Background: Parvovirus B19 (B19V) can cause severe relapsing episodes of pure red cell aplasia in immunocompromised individuals, which are commonly treated with intravenous immunoglobulins (IVIGs). Few data are available on B19V intra-host evolution and the role of humoral immune selection. Here, we report the dynamics of genomic mutations and subsequent protein changes during relapsing infection. Methods: Longitudinal plasma samples from immunocompromised patients with relapsing B19V infection in the period 2011–2019 were analyzed using whole-genome sequencing to evaluate intra-host evolution. The impact of mutations on the 3D viral protein structure was predicted by deep neural network modeling. Results: Of the three immunocompromised patients with relapsing infections for 3 to 9 months, one patient developed two consecutive nonsynonymous mutations in the VP1/2 region: T372S/T145S and Q422L/Q195L. The first mutation was detected in multiple B19V IgG-seropositive follow-up samples and resolved after IgG seroreversion. Computational prediction of the VP1 3D structure of this mutant showed a conformational change in the proximity of the antibody binding domain. No conformational changes were predicted for the other mutations detected. Discussion: Analysis of relapsing B19V infections showed mutational changes occurring over time. Resulting amino acid changes were predicted to lead to a conformational capsid protein change in an IgG-seropositive patient. The impact of humoral response and IVIG treatment on B19V infections should be further investigated to understand viral evolution and potential immune escape. Full article

Cell adhesion molecules (CAMs) are cell-surface-localized proteins mediating interactions of cells with other cells and the extracellular matrix. CAMs influence cell behavior and survival by inducing various intracellular signaling cascades that regulate diverse cellular processes including cytoskeleton remodeling and gene expression. Here, we review the evidence demonstrating that the levels, subcellular distribution, and binding affinities of CAMs of several major families including integrins, cadherins, immunoglobulin superfamily, and selectins are regulated by intracellularly generated or extracellular reactive oxygen species (ROS). Remarkably, CAMs themselves induce ROS production in response to binding to their ligands by activating lipoxygenases or NADPH oxidases or influencing ROS generation in mitochondria. CAM-dependent ROS production is essential for CAM-mediated cell adhesion and CAM-dependent intracellular signaling. Importantly, CAMs also protect cells from the ROS-induced cell death by stimulating the synthesis of antioxidants and suppressing the cell death signaling. A better understanding of the role ROS play in controlling CAM functions and mechanisms of this control may pave the way to modulating the functions of CAMs in various disorders associated with abnormal cell adhesion. Full article

DNA-deaminase AID plays a pivotal role in adaptive immunity, antibody diversification and epigenetic regulation. AID catalyzes cytidine deamination in immunoglobulin genes, facilitating somatic hypermutation (SHM), class-switch recombination (CSR) and gene conversion (GC). However, the dysregulation of AID activity can lead to oncogenic mutations and immune disorders such as hyper-IgM syndrome type 2 (HIGM2). At present the number of studies investigating the role of AID polymorphic variants in the promotion of pathology is low. The current review examines the structural and functional aspects of AID, focusing on the impact of amino acid substitutions—both natural polymorphisms and artificial mutations—on its catalytic activity, substrate binding and interactions with regulatory proteins. Additionally, a bioinformatic analysis of single-nucleotide polymorphisms of AID deposited in the dbSNP database was performed. SNPs leading to amino acid substitutions in the primary protein structure were analyzed. The bioinformatic analysis of SNPs in the AID gene predicts that among 208 SNPs causing amino acid substitutions in the primary protein structure, 62 substitutions may have significant negative impact on the functioning of AID. The integration of computational predictions with experimental data underscores the importance of AID regulation in maintaining immune homeostasis and highlights potential markers for immune-related pathologies. This comprehensive analysis provides insights into the molecular mechanisms of AID dysfunction and its implications for disease. Full article

Immunosuppression dramatically increases tissue and organ susceptibility to infection, injury, and even cancer. This poses a serious threat to human and animal health. In a previous study, we established a platform for high-throughput design and screening of multifunctional peptides. Using this platform, we successfully identified a novel hybrid peptide, VLP-Aβ (VA), which exhibits both immunomodulatory and antioxidant properties. This study aimed to evaluate the immunomodulatory activity of VA and investigate the underlying molecular mechanisms. In the cyclophosphamide (CTX)-induced immunodeficient mouse model, VA significantly alleviated CTX-induced weight loss. It also restored thymus and spleen indices, and increased serum immunoglobulins (IgA, IgM, IgG) and cytokines (TNF-α, IL-6, IL-1β) levels. VA also improved splenic lymphocyte proliferation, CD4⁺/CD8⁺ T cell ratios, and NK cell cytotoxicity. At the cellular level, western blot analysis showed that VA activated the TLR4-NF-κB pathway in RAW264.7 macrophages. Mechanistically, inhibition of the MD2 protein by L6H21 abolished VA’s immunomodulatory effects. This confirms MD2 as a critical mediator. Molecular docking and dynamics simulations revealed that VA binds stably to the hydrophobic pocket of MD2. These findings suggest that VA exerts immunomodulatory effects by stimulating MD2 and activating the TLR4-NF-κB pathway, which provides new ideas, techniques, and approaches for the development of novel peptide immunomodulators. Full article

It is becoming evident that the therapeutic effect of reawakening the immune response is to limit tumor cell growth and expansion. The use of immune checkpoint inhibitors, like blocking antibodies against programmed cell death receptor (PD) 1 and/or cytotoxic T lymphocyte antigen (CTLA) 4 alone or in combination with other drugs, has led to unexpected positive results in some tumors but not all. Several other molecules inhibiting lymphocyte antitumor effector subsets have been discovered in the last 30 years. Herein, we focus on the leukocyte-associated immunoglobulin (Ig)-like receptor 1 (LAIR1/CD305). LAIR1 represents a typical immunoregulatory molecule expressed on almost all leukocytes, unlike other regulatory receptors expressed on discrete leukocyte subsets. It bears two immunoreceptor tyrosine-based inhibitory motifs (ITIMs) in the intracytoplasmic protein domain involved in the downregulation of signals mediated by activating receptors. LAIR1 binds to several ligands, such as collagen I and III, complement component 1Q, surfactant protein D, adiponectin, and repetitive interspersed families of polypeptides expressed by erythrocytes infected with Plasmodium malariae. This would suggest LAIR1 involvement in several cell-to-cell interactions and possibly in metabolic regulation. The presence of both cellular and soluble forms of LAIR would indicate a fine regulation of the immunoregulatory activity, as happens for the soluble/exosome-associated forms of PD1 and CTLA4 molecules. As a consequence, LAIR1 appears to play a role in some autoimmune diseases and the immune response against tumor cells. The finding of LAIR1 expression on hematological malignancies, but also on some solid tumors, could open a rationale for the targeting of this molecule to treat neoplasia, either alone or in combination with other therapeutic options. Full article

B Cell Maturation Antigen (BCMA) has gained considerable attention as a target in directed therapies for multiple myeloma (MM) treatment, via immunoglobulin-based bispecific T cell engagers or CAR T cell strategies. We describe the development of alternative, non-immunoglobulin BCMA-recognising affinity proteins, based on the small (58 aa) three-helix bundle affibody scaffold. A first selection campaign using a naïve affibody phage library resulted in the isolation of several BCMA-binding clones with different kinetic profiles. One clone showing the slowest dissociation kinetics was chosen as the template for the construction of two second-generation libraries. Characterization of output clones from selections using these libraries led to the identification of clone 1-E6, which demonstrated low nM affinity to BCMA and high thermal stability. Biosensor experiments showed that 1-E6 interfered with the binding of BCMA to both its natural ligand APRIL and to the clinically evaluated anti-BCMA monoclonal antibody belantamab, suggesting overlapping epitopes. A fluorescently labelled head-to-tail homodimer construct of 1-E6 showed specific binding to the BCMA⁺ MM.1s cell line in both flow cytometry and fluorescence microscopy. Taken together, the results suggest that the small anti-BCMA affibody 1-E6 could be an interesting alternative to antibody-based affinity units in the development of BCMA-targeted therapies and diagnostics. Full article

The whey protein (WP) fraction represents 18–20% of the total milk nitrogen content. It was originally considered a dairy industry waste, but upon its chemical characterization, it was found to be a precious source of bioactive components, growing in popularity as nutritional and functional food ingredients. This has generated a remarkable increase in interest in applications in the different sectors of nutrition, food industry, and pharmaceutics. WPs comprise immunoglobulins and proteins rich in branched and essential amino acids, and peptides endowed with several biological activities (antimicrobial, antihypertensive, antithrombotic, anticancer, antioxidant, opioid, immunomodulatory, and gut microbiota regulation) and technological properties (gelling, water binding, emulsification, and foaming ability). Currently, various process technologies and biotechnological methods are available to recover WPs and convert them into BioActive Peptides (BAPs) for commercial use. Additionally, in silico approaches could have a significant impact on the development of novel foods and/or ingredients and therapeutic agents. This review provides an overview of current and emerging methods for the production, selection, and application of whey peptides, offering insights into bioactivity profiling and potential therapeutic targets. Recent updates in legislation related to commercialized WPs-based products are also presented. Full article

Background: N-glycosylation is a post-translational modification involving the attachment of oligosaccharides to proteins and is known to influence immunoglobulin G (IgG) effector functions and even antigen binding. IgG contains an evolutionarily conserved N-glycosylation site in its fragment crystallizable (Fc) region, while during V-D-J recombination and somatic hypermutation processes it can also obtain N-glycosylation sites in its antigen binding fragment (Fab). Our previous study demonstrated altered IgG N-glycosylation in children at type 1 diabetes (T1D) onset, with the most prominent changes involving sialylated glycans, hypothesized to mainly come from the Fab region, however, the analytical method used could not distinguish between Fc and Fab. Methods: IgG was isolated from plasma from 118 children with T1D and 98 healthy controls from the Danish Registry of Childhood and Adolescent Diabetes. Isolated IgG was cleaved into Fc and Fab fragments using IdeS enzyme. N-glycans were enzymatically released from each fragment, fluorescently labelled with procainamide, and analyzed separately using the UPLC-MS method. Structural annotation of resulting chromatograms was performed using MS/MS. Results: T1D related N-glycosylation changes were more pronounced in the Fab glycans compared to Fc glycans, with five Fab glycans (Man5, Man7, FA2BG1S1, A2G2S2, FA2BG2S1) being significantly altered compared to only one in the Fc region (FA2[3]BG1). Comparing Fc and Fab glycosylation overall reveals stark differences in the types of glycans on each region, with a more diverse and complex repertoire being present in the Fab region. Conclusions: These findings suggest that N-glycosylation changes in early onset T1D predominantly originate from the Fab region, underscoring their potential role in modulating (auto)immunity and highlighting distinct glycosylation patterns between Fc and Fab. Full article

Reducing the allergenicity of food components through processing is attracting great attention in the food industry. This study investigated the structure and allergenicity of complexes formed from peanut protein (PP) and rice protein (RP) using the pH-driven method. The properties of the PP–RP complexes were investigated using morphological analysis, multi-spectroscopic characterization, IgE binding capacity analysis, and in vitro digestibility studies. Morphological analysis showed that the complexes lost their particulate structures after pH-driven treatment. Spectroscopic analysis showed that the pH-driven treatment promoted protein structural changes, making them more susceptible to degradation. There were also changes in the tertiary structures of the proteins in the complexes following the pH-driven treatment. The IgE binding capacity and digestibility studies suggested that the pH-driven treatment reduced the potential allergenicity of PP by altering its structure under gastrointestinal conditions. This study provides a promising approach for producing hypoallergenic peanut protein ingredients for use in the food industry. Full article

An increase in immunoglobulin G4 (IgG4) levels is typically associated with immunological tolerance states and develops after prolonged exposure to antigens. Accordingly, IgG4 is considered an anti-inflammatory antibody with a limited ability to trigger efficient immune responses. Additionally, IgG4 reduces allergic reactions by blocking immunoglobulin E (IgE) activity. In the case of COVID-19, it has been reported that the repeated administration of some vaccines induces high IgG4 levels. The latest research data have revealed a surprising IgE anti-receptor binding domain response after both natural infection and several SARS-CoV-2 vaccines. The presence of IgG4 and IgE in COVID-19 disease suggests that the virus may induce an “allergic-like” response to evade immune surveillance, leading to a shift from T helper 1 (Th1) to T helper 2 (Th2) cells, which promotes tolerance to the virus and potentially contributes to chronic infection. The spike protein from vaccines could also induce such a response. Interestingly, “allergen-like” epitopes and IgE responses have been reported for other viruses, such as influenza, human immunodeficiency virus (HIV), and respiratory syncytial virus (RSV). The impact of this viral-induced tolerance will be discussed, concerning long COVID and the protective efficacy of vaccines. Full article

Shrimp are highly favored by consumers for their delicious taste and rich nutritional value. However, reports of allergic reactions caused by shrimp and its derivatives have been increasing, significantly impacting consumer health and posing a growing global food safety concern. This article introduces the structure and biochemical characteristics of major allergenic proteins in shrimp, including tropomyosin (TM), arginine kinase, sarcoplasmic calcium-binding protein, myosin light chain, troponin C, and hemocyanin. Currently, there is no effective treatment for shrimp allergies, and prevention is mainly achieved by avoiding consumption. The study of shrimp allergen sensitization reduction technology is of great significance to the development of hypoallergenic or desensitized products. The article provides a detailed overview of the effects of common processing techniques, including physical, chemical, biological, and combined methods, on the allergenicity of shrimp allergens; for instance, the binding rate to immunoglobulin E (IgE) was reduced by 73.59% after treating TM with high pressure (500 MPa) at 55 °C for 10 min and the recognition rate of TM to IgE decreased by 89.4% on average after treating TM with pepsin (30 μg/mL, pH 2) for 2 h. These techniques provide references for the development of hypoallergenic aquatic products or desensitized foods. Full article

Identifying reliable biomarkers in peripheral blood is critical for advancing the diagnosis and management of multiple sclerosis (MS), particularly given the invasive nature of cerebrospinal fluid (CSF) sampling. This review explores the role of B cells and immunoglobulins (Igs), particularly IgG and IgM, as biomarkers for MS. B cell oligoclonal bands (OCBs) in the CSF are well-established diagnostic tools, yet peripheral biomarkers remain underdeveloped. Emerging evidence highlights structural and functional variations in immunoglobulin that may correlate with disease activity and progression. A recent novel discovery of blood IgG aggregates in MS patients that fail to bind Protein A reveals promising diagnostic potential and confirms previous findings of the unique features of immunoglobulin G in MS and the potential link between the superantigen Protein A and MS. These aggregates, enriched in IgG1 and IgG3 subclasses, exhibit unique structural properties, including mutations in the framework region 3 (FR3) of IGHV3 genes, and are associated with complement-dependent neuronal apoptosis. Data based on ELISA have demonstrated that IgG aggregates in plasma can distinguish MS patients from healthy controls and other central nervous system (CNS) disorders with high accuracy and differentiate between disease subtypes. This suggests a role for IgG aggregates as non-invasive biomarkers for MS diagnosis and monitoring. Full article

Sialic acids serve as crucial terminal sugars on glycoproteins or glycolipids present on cell surfaces. These sugars are involved in diverse physiological and pathological processes through their interactions with carbohydrate-binding proteins, facilitating cell–cell communication and influencing the outcomes of bacterial and viral infections. The role of hypersialylation in tumor growth and metastasis has been widely studied. Recent research has highlighted the significance of aberrant sialylation in enabling tumor cells to escape immune surveillance and sustain their malignant behavior. Acute lymphoblastic leukemia (ALL) is a heterogenous hematological malignancy that primarily affects children and is the second leading cause of mortality among individuals aged 1 to 14. ALL is characterized by the uncontrolled proliferation of immature lymphoid cells in the bone marrow, peripheral blood, and various organs. Sialic acid-binding immunoglobulin-like lectins (Siglecs) are cell surface proteins that can bind to sialic acids. Activation of Siglecs triggers downstream reactions, including induction of cell apoptosis. Siglec-7 and Siglec-9 have been reported to promote cancer progression by driving macrophage polarization, and their expressions on natural killer cells can inhibit tumor cell death. This comprehensive review aims to explore the sialylation mechanisms and their effects on ALL in children. Understanding the complex interplay between sialylation and ALL holds great potential for developing novel diagnostic tools and therapeutic interventions in managing this pediatric malignancy. Full article

A fast and simple biotech method is presented for the simultaneous isolation and purification of transferrin (Tf) and immunoglobulin G (IgG) from the same pool-sample of human serum, yielding >98% pure proteins. Serum sample preparation was achieved by precipitation with ethacridine lactate (rivanol). Protein purification was performed with AKTA Avant 150 FPLC, using a Resource Q column. Three different buffers at pH 6.2 (MES, phosphate, and Bis-Tris) were tested. Isolated and purified proteins retained their native 3D structure, as shown by spectrofluorimetric measurements. Tf functionality was preserved, as confirmed by the retention of both the iron binding capacity and its ability to interact with the transferrin receptor (immunofluorescent staining), as well as the immunogenicity of IgG, as shown by Western blot analysis with immunodetection. The formation of IgG aggregates was avoided. This biotech method is a rapid, simple, and time-saving alternative to other methods for the isolation of extremely pure IgG and Tf, while it is also the only method so far described for their simultaneous isolation. Full article